Responding to the rapidly increasing demand for efficient energy usage and increased speed and functionality of electronic and spintronic devices, multiferroic oxides have recently emerged as key materials capable of tackling this multifaceted challenge. In this paper, we describe the development of single-site manganese-based multiferroic perovskite materials with modest amounts of nonmagnetic Ti substituted at the magnetic Mn site in $\mathrm{S}{\mathrm{r}}_{1-x}\mathrm{B}{\mathrm{a}}_x\mathrm{M}{\mathrm{n}}_{1-y}\mathrm{T}{\mathrm{i}}_y{\mathrm{O}}_3$ (SBMTO). Significantly enhanced properties were achieved with ferroelectric-type structural transition temperatures boosted to $\sim 430\mathrm{K}$. Ferroelectric distortions with large spontaneous polarization values of $\sim 30\mu \mathrm{C}/\mathrm{c}{\mathrm{m}}^2$, derived from a point charge model, are similar in magnitude to those of the prototypical nonmagnetic $\mathrm{BaTi}{\mathrm{O}}_3$. Temperature dependence of the system's properties was investigated by synchrotron x-ray powder diffraction and neutron powder diffraction at ambient and high pressures. Various relationships were determined between the structural and magnetic properties, Ba and Ti contents, and $T_{\mathrm{N}}$ and $T_{\mathrm{C}}$. Most importantly, our results demonstrate the large coupling between the magnetic and ferroelectric order parameters and the wide tunability of this coupling by slight variations of the material's stoichiometry.

• Received 22 May 2019

DOI:https://doi.org/10.1103/PhysRevMaterials.3.084401